Electrodeposition and characterization of nano-structured Ni-SiC composite films

Ni-SiC nano-composite coating, which simultaneously composed of both nanocrystalline consecutive Ni matrix and dispersed inert SiC nano-particles, has been fabricated by ultrasonic electroplating technique from a modified Watts bath containing SiC nano-particles. The influence of mechanical stirring and ultrasonication on the surface morphology of the nanocrystalline Ni-SiC nano-composite film has also been investigated. The surface morphology, microstructure, anti-corrosion property and electrocatalytic activity for hydrogen evolution of the obtained nanocrystalline Ni-SiC nano-composite film, are characterized using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) system, atomic force microscopy (AFM), transmission electron microscope (TEM), X-ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS) techniques. The results find that, mechanical stirring mainly prevents the sedimentation of the inert particles suspended in solutions, while ultrasonication mainly prevents the particles agglomeration. In the case of only mechanical stirring to disperse the SIC nano-particles, the composite surface is cauliflower alike. While in the case of both mechanical stirring and ultrasonication, the obtained Ni-SiC composite film is much smoother and composes of particles with the mean diameter of 42.9 nm, and SiC particles are uniformly dispersed into Ni matrix. Meanwhile, the results obtained by polarization curves and EIS methods show that, when compared with the traditional polycrystalline Ni film, the obtained Ni-SiC nano-composite film exhibits the enhanced corrosion resistance in NaCl solutions, possesses much higher electrocatalytic activity for hydrogen evolution in KOH solutions. (C) 2010 Elsevier B.V. All rights reserved.